The present invention relates generally to the field of sound dampening materials, and more particularly to plaster-based materials having improved sound dampening properties.
Plaster-based materials are used in a variety of building and construction applications where sound dampening properties are desirable. For example, gypsum panels are used in wall, door, floor, ceiling, roof, and other building applications. In multi-family and commercial buildings, floor/ceiling assemblies commonly include plaster-based materials as part of the subfloor structure. For example, gypsum underlayments are typically applied over structural concrete or precast concrete planks in floor/ceiling assemblies to create a smooth, monolithic floor surface that delivers superior strength, sound control, and fire resistance as compared to Portland cement and other products.
To mitigate impact or airborne related noise from transferring through such structures, acoustical sound mats are commonly laid over concrete or wood subfloors. The mats are a fabric material which creates an air space between the subfloor and gypsum underlayment. The air space serves to mechanically isolate and decouple impact related vibrations. The sound mat is typically topped with a pumpable, sanded gypsum underlayment ¾ to 1 inch thick and screeded to maintain a uniform depth and finish.
However, there are drawbacks to the current system. For example, acoustical sound mats are very expensive per square foot and are time consuming and costly to install. Sound mats are also prone to shift under heavy loads and/or from hard impacts, which can cause flooring or tiles to crack. For this reason, another costly reinforcement-type mat or an even more expensive metal lathing is commonly installed overtop the sound mats before the gypsum underlayment is poured. Additionally, the acoustical mats create a mechanical air space but do little to abate sound vibrations at low to mid frequencies and must rely predominately on the mass of the assembly for abatement of these vibrations.
Accordingly, there is a need for materials having improved sound dampening properties.